Hair brain-derived neurotrophic factor (BDNF) as predictor of developing psychopathological symptoms in childhood.

BACKGROUND: Dysregulation in the expression of neurotrophins is implicated in the pathophysiology of several mental disorders. Peripheral brain-derived neurotrophic factor (BDNF) can be measured in hair and might represent a marker of adequate neuroplasticity regulation. In early developmental periods, neuroplasticity regulation might be particularly important, but BDNF markers have not yet been analyzed in this regard. We used the hair-BDNF concentration (HBC) to investigate the prediction of emerging symptoms of anxiety/depressive and attention-deficit hyperactivity disorder (ADHD) in the developmentally crucial period from preschool to school age. METHODS: 117 children (58 girls, 59 boys) participated in a longitudinal study at the ages of 4-5 (T1) and 8 (T2) years. At T1, HBC was measured in a 3 cm hair segment. At T1 and T2, symptom domains were assessed using a multi-method (clinical interview, questionnaire) and multi-informant approach. RESULTS: T1 HBC was significantly negatively associated with T1 anxiety/depressive symptoms (r = -0.27) and predicted T2 anxiety disorder symptoms (r = -0.34) after controlling for the T1 symptoms. T1 HBC also predicted T2 depressive disorder symptoms (r = -0.18) but was not associated with ADHD symptom development. LIMITATIONS: BDNF hair analysis is a new method with a not yet large number of studies on methodological issues. Our study adds evidence to the validity of the method. CONCLUSIONS: Prediction of anxiety/depressive symptom development by HBC was shown. As this study was the first to use HBC in this context, cross-validation is necessary and worthwhile. HBC might prove to constitute a useful, non-invasive early marker of risk for anxiety/depressive disorders in childhood.

Increased hair cortisol in mothers of children with ADHD symptoms and psychosocial adversity background.

Parents of children with attention deficit hyperactivity disorder (ADHD) have shown high perceived parenting stress. Hence, physiological adjustment processes, involving the hypothalamic-pituitary-adrenal axis, seem possible. We hypothesized that (1) ADHD symptoms of the child predict an increase of maternal hair cortisol concentration (HCC), and (2) presence of psychosocial adversity amplifies the prediction. We analyzed a preschool-aged sample using a longitudinal design (T1, at the children's age of 4 years; T2, 12 months later). 128 mothers and their children participated in the study. To determine HCC of the previous 3 months, the first scalp-near 3 cm hair segment was used. ADHD symptoms of the child were measured using teacher- and parent-report questionnaires and a clinical interview with the mother. The T1 teacher-reported ADHD symptoms score of the child was significantly positively associated with the mother`s T1 and T2 HCC score. In families with high psychosocial adversity, the prediction of an increase in maternal HCC by the teacher-reported ADHD symptoms of child was significantly stronger than in low-adversity families. In presence of psychosocial family adversity, ADHD symptoms of the child predicted an increase in the mother's HCC. As a continuously high cortisol level implicates health risks and might in turn affect parenting resources, the identifying of caregivers at risk through biological markers of stress could be helpful for planning targeted interventions. As our study is the first on this issue, cross-validation is needed.

Reward-Related Dysfunctions in Children Developing Attention Deficit Hyperactivity Disorder-Roles of Oppositional and Callous-Unemotional Symptoms.

Objectives: Neurocognitive functions might indicate specific pathways in developing attention deficit hyperactivity disorder (ADHD). We focus on reward-related dysfunctions and analyze whether reward-related inhibitory control (RRIC), approach motivation, and autonomic reactivity to reward-related stimuli are linked to developing ADHD, while accounting for comorbid symptoms of oppositional defiant disorder (ODD), and callous-unemotional (CU) traits. Methods: A sample of 198 preschool children (115 boys; age: m = 58, s = 6 months) was re-assessed at age 8 years (m = 101.4, s = 3.6 months). ADHD diagnosis was made by clinical interviews. We measured ODD symptoms and CU traits using a multi-informant approach, RRIC (Snack-Delay task, Gift-Bag task) and approach tendency using neuropsychological tasks, and autonomic reactivity via indices of electrodermal activity (EDA). Results: Low RRIC and low autonomic reactivity were uniquely associated with ADHD, while longitudinal and cross-sectional links between approach motivation and ADHD were completely explained by comorbid ODD and CU symptoms. Conclusion: High approach motivation indicated developing ADHD with ODD and CU problems, while low RRIC and low reward-related autonomic reactivity were linked to developing pure ADHD. The results are in line with models on neurocognitive subtypes in externalizing disorders.

Mother's hair cortisol and symptoms of attention deficit hyperactivity disorder in her preschool child.

Children with attention deficit hyperactivity disorder (ADHD) require increased caregiver assistance and supervision, and their parents have shown high perceived parenting stress. Hence, physiological adjustment processes in the caregivers, involving the hypothalamic-pituitary-adrenal axis, seem plausible. We analyzed the association between maternal hair cortisol concentration (HCC) and symptoms of ADHD in preschool-aged children. 150 mothers of 4-5-year-old children participated in the study. To determine the HCC, the first scalp-near 3 cm hair segment was used. ADHD symptoms of the child were measured using teacher- and parent-report questionnaires and a clinical interview with the mother. When controlling for several putative confounders, teacher-reported ADHD symptoms were significantly positively associated with mothers' HCC. No associations of HCC with the mother-reported ADHD symptoms of the child emerged. It is possible that teacher-reported ADHD symptoms of the child reflect relevant ADHD symptoms more validly. As our study is the first on this issue, cross-validation is needed.